In a current communication system, active research is being conducted in order to provide users with services having a variety of quality of services (QoS) at a high transmission rate. In the communication system, research for providing a large capacity service including a variety of QoS using limited resources, for example, frequency resources is actively ongoing. In particular, with development in a propagation communication technology and appearance of a new wireless communication technology, a necessity to more efficiently use finite frequency resources is being emphasized.
As a method for increasing use efficiency of limited frequency resources in the communication system, proposed are methods of optimizing performance of the communication system, for example, methods for maximizing the spectrum efficiency through multiple access, encoding, modulation, information compression, and the like, and also minimizing interference with a communication system using a different scheme. Proposed is a frequency sharing method for increasing use efficiency of frequency resources using a frequency band available in a frequency band already being used, such as a television (TV) band.
Here, in the aforementioned method of sharing a frequency in a frequency band available in a frequency band already being used such as a TV band, the available frequency band needs to be used without causing interference against a primary incumbent having the precedence right to use the TV band and thus, it is important to detect the available frequency band by verifying whether the primary incumbent is using the frequency band in the TV band. When a plurality of different systems desiring to use the available frequency band detected in the TV band is present, there is difficulty in coexisting with the available frequency band due to a difference in communication scheme between the plurality of different systems, for example, a wireless access scheme, and the like.
A mutual coexistence technology refers to a spectrum management technology that enables wireless devices using different communication protocols to mutually coexist without causing harmful interference in a core frequency (30 MHz to 10 GHz) in which various dynamic spectrum access (DSA) technologies are predicted to appear. A DSA technology is a concept opposite to a current static spectrum management technology, and refers to a wireless access and management technology that maximizes flexibility and efficiency of using a frequency by dynamically managing a spectrum based on a peripheral propagation environment of a wireless device. A technology is developed to induce a mutual coexistence criterion capable of effectively operating a plurality of sharing technologies on a national level for spectrum management in preparation for frequency sharing technologies that are variously appearing for each wireless service, such as the Institute of Electrical and Electronics Engineers (IEEE) 802, SCC 41, and the like.
Domestically, research on an integrated mutual coexistence condition of various sharing technologies for securing the optimal frequency efficiency in an interfering propagation environment such as a frequency auction system, sharing of a license band and a non-license band, and the like, is not being conducted systematically. The IEEE 802.19, which is an international standardization organization, refers to a wireless coexistence working group (WG) that handles a coexistence issue between 802 standards, and is discussing technical issues on a coexistence scenario between wireless systems that share a frequency in a license band and a non-license band, mutual coexistence analysis, a sharing mechanism for the mutual coexistence, and the like.